Slow 0.1 Hz Breathing and Body Posture Induced Perturbations of RRI and Respiratory Signal Complexity and Cardiorespiratory Coupling

Abstract

Objective: We explored the physiological background of the non-linear operating mode of cardiorespiratory oscillators as the fundamental question of cardiorespiratory homeodynamics and as a prerequisite for the understanding of neurocardiovascular diseases. We investigated 20 healthy human subjects for changes using electrocardiac RR interval (RRI) and respiratory signal (Resp) Detrended Fluctuation Analysis (DFA, α 1RRI , α 2RRI , α 1Resp , α 2Resp), Multiple Scaling Entropy (MSE RRI1−4 , MSE RRI5−10 , MSE Resp1−4 , MSE Resp5−10), spectral coherence (Coh RRI−Resp), cross DFA (ρ 1 and ρ 2) and cross MSE (X MSE1−4 and X MSE5−10) indices in four physiological conditions: supine with spontaneous breathing, standing with spontaneous breathing, supine with 0.1 Hz breathing and standing with 0.1 Hz breathing. Main results: Standing is primarily characterized by the change of RRI parameters, insensitivity to change with respiratory parameters, decrease of Coh RRI−Resp and insensitivity to change of in ρ 1 , ρ 2 , X MSE1−4 , and X MSE5−10. Slow breathing in supine position was characterized by the change of the linear and non-linear parameters of both signals, reflecting the dominant vagal RRI modulation and the impact of slow 0.1 Hz breathing on Resp parameters. Coh RRI−Resp did not change with respect to supine position, while ρ 1 increased. Slow breathing in standing reflected the qualitatively specific state of autonomic regulation with striking impact on both cardiac and respiratory parameters, with specific patterns of cardiorespiratory coupling. Significance: Our results show that cardiac and respiratory short term and long term complexity parameters have different, state dependent patterns. Sympathovagal non-linear interactions are dependent on the pattern of their activation, having different scaling properties when individually activated with respect to the state of their joint activation. All investigated states induced a change of α 1 vs. α 2 relationship, which can be accurately expressed by the proposed measure-inter-fractal angle θ. Short scale (α 1 vs. MSE 1−4) and long scale (α 2 vs. MSE 5−10) complexity measures had reciprocal interrelation in standing with 0.1 Hz breathing, with specific cardiorespiratory coupling pattern (ρ 1 vs. X MSE1−4). These results support the hypothesis of hierarchical organization Matić et al. RRI-Respiratory Complexity and Cardiorespiratory Coupling of cardiorespiratory complexity mechanisms and their recruitment in ascendant manner with respect to the increase of behavioral challenge complexity. Specific and comprehensive cardiorespiratory regulation in standing with 0.1 Hz breathing suggests this state as the potentially most beneficial maneuver for cardiorespiratory conditioning.

Unexpected Cardiovascular Oscillations at 0.1 Hz During Slow Speech Guided Breathing (OM Chanting) at 0.05 Hz

“…It has been shown that the body position affects cardiac autonomic regulation and cardiorespiratory regulation during slow paced breathing at 0.1 Hz. Complexities on short and long-term scales and also self-similarities of the RR interval series change between standing and supine position as well as between spontaneous breathing and slow-paced breathing at 0.1 Hz ( Matic et al, 2020 ). Furthermore, the coherence between interbeat intervals and respiration was lower during standing compared to the supine position.…”

Targeting MMP-Regulation of Inflammation to Increase Metabolic Tolerance to COVID-19 Pathologies: A Hypothesis

“…However, MMPs are mediators of tissue and organ damage when their activity is pathologically elevated, as demonstrated by earlier research for MMPs in comorbidities that accompany severe COVID-19 cases [ 1 , 10 , 11 ]. In response to infection with SARS-CoV-2 (and possibly other pathogens), the host’s immune and target cells are likely to release MMPs because one of the physiological stimuli that cause all cells to alter their production and release MMPs is inflammation, which itself is modulated by the MMP-mediated cleavage of cytokines and chemokines [ 25 , 26 , 29 , 76 , 77 , 78 , 79 ]. SARS-CoV-2 infection and the comorbidities that accompany COVID-19 are pro-inflammatory on their own, and their superimposition exacerbates inflammation.…”

Heart rate and cardiac autonomic responses to concomitant deep breathing, hand grip exercise, and circulatory occlusion in healthy young adult men and women

“…The rhythmic entrainment and related salutary effects of deep breathing (DB) are likely mediated by activation of the Hering-Breuer reflex, related improvements in baroreflex sensitivity, and increased cardiac vagal tone and decreased cardiac sympathetic tone [ 6 , 7 ]. While there is evidence that DB offers a non-pharmacological strategy to improve cardiac autonomic function [ 8 ], there are other non-pharmacological therapies that have been shown to have similar effects, such as isometric handgrip exercise [ 9 ].…”

“…Importantly, it has been shown that this training modality produces significant and clinically meaningful reductions in heart rate (HR) and blood pressure (BP) [ 10 ], and better cardiovascular outcomes compared to dynamic aerobic and/or resistance exercise [ 10 ]. The beneficial effects of HG exercise on cardiovascular function are likely related to the activation of the mechano-metaboreflex during muscle contraction [ 8 , 11 , 12 ]. Mechanical compression and metabolite accumulation within the muscle tissue during HG stimulates mechano/metabo sensitive afferent fibers (groups III and IV) which promote sympathoexcitation and parasympathetic withdrawal [ 8 , 11 , 12 ].…”

“…The beneficial effects of HG exercise on cardiovascular function are likely related to the activation of the mechano-metaboreflex during muscle contraction [ 8 , 11 , 12 ]. Mechanical compression and metabolite accumulation within the muscle tissue during HG stimulates mechano/metabo sensitive afferent fibers (groups III and IV) which promote sympathoexcitation and parasympathetic withdrawal [ 8 , 11 , 12 ]. Interestingly, it has been proposed that circulatory occlusion (OC) through external compression of muscle would likely elicit comparable effects on the neural regulation of cardiovascular function as the ones observed during HG exercise [ 12 ].…”